Electrical energizing means for



March 18, 1952 E Re. 23,470

ELECTRICAL ENERGIZING MEANS FOR LIMIT CONTROL DEVICES AND THE LIKE Origmal Filed May 24 1949 A.C.INPUT AC. OUTPUT INVENTOR. Blub L. Beiz.

ATTORNEYS WWW/rim Reiasued Mar. 18, 1952 ELECTRICAL ENERGIZING MEANS FOR LIIVHT CONTROL DEVICES AND THE LIKE Paul L. Betz, Baltimore, Md., assignor to Consolidated Gas Electric Light and Power Company of Baltimore, Baltimore, Md., a corporation of Maryland Original No. 2,569,397, dated September 25, 1951,

Serial No. 95,130, May 24, 1949.

Application for reissue October 26, 1951, Serial No. 253,323

8 Claims.

Matter enclosed in heavy brackets I:

] appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue.

This invention in its broader aspects relates to an electrical device which, upon opening of a circuit therein, causes an impulse to be generated which may be used to actuate an electrically or electromagnetically controlled mechanism. In a narrower sense, and as a specific application of such a device, the present invention relates to an electrical device which, upon opening of a circuit therein, will cause a thermoelectrically controlled mechanism to be operated, notwithstanding the continued generation of thermoelectric current, as if the thermoelectric current had passed below a predetermined value. By way of illustration, the invention will be particularly explained with respect to its latter use, but it is to be understood that the electrical device for generating an impulse. on opening of a circuit is of wider utility as will be apparent to those skilled in the art.

In many electrical circuits energization of limit control means is effected by closing a switch in a control circuit. For example, in my pending application Serial No. 653,494, filed March 11, 1946, now Patent No. 2,505,730, dated April 25, 1950, I have disclosed a thermoelectrically actuated shut-off valve used to control the flow of fuel to a main burner. A pilot burner associated with the main burner serves the double purpose of igniting the fuel at the main burner and of heating the hot junction of the thermocouple of the shut-off valve. The main burner in this example supplies heat to a water heater, the tank of which is provided with a switch responsive to the temperature or pressure of the water within the tank. This switch is so arranged that as long as the water temperature or pressure is below a predetermined value, the switch contacts remain open, and, upon attainment of the predetermined temperature or pressure, the contacts close. Closure of the switch contacts causes alternating current to be supplied to the thermoelectric circuit of the shutoff valve to cause the valve to close. The switch is required to close only when an abnormal temperature or pressure occurs. In said application this limit control operation is accomplished by the superposition of alternating current on the direct current of the thermocouple, and this causes the shut-off to close even though normal thermoelectric current is flowing.

In certain cases it is desirable that the superposition of alternating current on the thermoelectric current be occasioned by the opening of a circuit, as by a switch, when an excessive temperature or pressure occurs, rather than a clos- 4.?

iii]

. parallel, the structed that when energized the resulting volt- 2 ing thereof. This introduces a [full-safe] failsafe characteristic, which may also be effective upon the occurrence of a broken wire, failure to make electrical contact, etc., tocause the shutoff valve to move to its inoperative position.

It is an object of this invention to provide an improved system to efiect actuation of a safety device upon opening of a control circuit.

Another object of this invention is to provide an improved electrical actuating device which, upon opening of a circuit therein, will generate an impulse that can be used to actuate an electrically or electromagentically controlled mechanism.

Another object of this invention is to provide a thermoelectrically controlled mechanism with improved electrical means which, upon the opening of a control circuit, will cause the thermoelectrically controlled mechanism to be actuated as if the thermoelectrical current had passed below a predetermined value.

Another object of this invention isto provide a device of the type characterized which is simple in construction and one which may be readily incorporated in existing systems as well as embodied in new systems for the purposes of effecting actuation of an electrically or electromagnetically controlled mechanism upon an opening of a control circuit.

In brief, the control device of the present invention comprises a pair of transformers having their secondary windings connected in series and their primary windings connected in secondary windings being so conage is zero or substantially zero, but when the, circuit of one of said primary windings is opened, the voltage generated in the secondary winding associated with the other primary winding is no longer balanced out, but is available for use in actuating an electrically or electromagnetically controlled [mechanim] mechanism. As applied to the actuation of a thermoelectrically controlled mechanism, said unbalanced voltage in the active secondary winding is utilized at the thermoelectrically controlled mechanism to produce an actuation thereof such as would arise if the thermoelectric current passed below a predeterminedvalue.

The invention is capable of being embodied in a variety of ways as will appear from the ensuing description, and it is therefore to be expressly understood that the embodiments selected for illustrating the application of the invention are not to be construed as defining the limits of the invention, reference being had to the appended claims for that purpose.

Referring in detail to the accompanying drawings, wherein the same reference characters are used to designate corresponding parts in the several figures,

Fig. 1 is an electrical diagram showing an embodiment of the electrical device for generating an impulse upon opening of a control circuit;

Fig. 2 is a diagram illustrating one way of applying the impulse derived from the device of Fig. 1 for actuation of a thermoelectrically controlled safety device;

Fig. 3 is a diagram illustrating another wayof applying the impulse derived from the device of Fig. l for actuating a thermoelectrically controlled safety device; and

Fig. 4 is a diagram illustrating yet another way of applying the impulse derived from the device of Fig. 1 for actuating a thermoelectrically controlled safety device.

Referring first to Fig. 1, two transformers Ill and 20 are indicated as having primary windings H and 2|, respectively, and secondary windings l2 and 2.2, respectively. The secondary windings |2 and 22 are connected in series to output leads including alternating current output terminals 30 and 3|. The primary-windings II and 2| are connected in parallel to alternating current input leads 4|! and 4| in circuit with any suitable source of alternating current. The secondary windings l2 and 22 of said transformers have such parameters that the voltages induced therein are equal or nearly equal in magnitude, and either the primary windings I and 2| or the secondary windings l2 and 22 are so connected that the voltages induced in the secondary windings l2 and 22 oppose each other to the end that the n'etvoltage output at the terminals 30 and 3| is zero or nearly so when both primaries are in circuit and are energized. In the form shown in Fig. 1 the primary windings II and 2| have 0pposite polarities as indicated by the arrows.

One of the parallel connections to the primaries I and 2| is provided with a normally closed switch 5|], here shown as disposed in the lead 5| which connects one end of the primary 2| to one side 40 of the alternating current input circuit.

When alternating current is supplied to the leads 4!) and 4| with switch 59 closed, the output voltage at the terminals 30 and 3| is zero or nearly so since the voltages in the secondary windings l2 and 22 are equal and of opposite polarity at every instant. Upon the occurrence of .an abnormal condition such that switch 50 is opened, the primary winding 2| of transformer 20 is de-energized. Thereupon the voltage induced in the secondary winding 22 becomes zero, out the voltage available at the terminals 30 and 3| rises from zero to approximately the voltage induced in the secondary winding l2. This alternating current output at the terminals 3|] and 3| may be utilized in any desired manner, the energy at these terminals becoming available upon opening the switch and unavailable as long as switch 53 is closed. The same operation as just described would also occur if there were a break in line 5| and therefore the switch 59 is to be taken as typifying any cause of opening the line 5|.

In Fig. -1 .the connections between the transformers If! and 2|! are such that the secondary windings l2 and 22 are in series with additive polarities and the primary windings and 2| are connected to the alternating current input leads 40 and 4| so as to induce voltages of opposite polarity in the secondary windings I2 and 22. As before indicated, other arrangements of the connections of the transformers l0 and 20 may be employed, the only requirement being that the secondary windings l2 and 22 are connected in series and the primary windings II and 2| are connected in parallel under such conditions that when the transformers l9 and 20 are energized the voltage induced at the alternating current output terminals 39 and 3! is zero or approximately zero.

Figs. 2, 3 and 4 illustrate three different ways in which the voltage at output terminals 30 and 3| existing when the line 5| is opened, as by the switch 5|], can be applied to a thermoelectrically controlled safety device to effect actuation thereof notwithstanding the continued generation of thermoelectric current.

Safety devicesare now well known which include an electromagnet or solenoid for holding a valve in open position, for example, as long as said electromagnet or solenoid is energized by thermoelectric current generated by a thermocouple subjected to the heat of a flame and operating on the principles disclosed in the patent granted to Sebastian Karrer, No. 2,097,838, on November 2, 1937. Upon failure of the source of thermoelectric current, however, the electromagnet or solenoid is de-energizegl so that the valve, in the illustration assumed, is closed, as by the action of gravity or a spring, if the flame at the thermocouple goes out. Conditions may arise, however, whereby it is desirable that the safety device close even though the flame at the thermocouple continues to generate normal thermoelectric current. Figs. 2, 3 and 4 illustrate how this result may be obtained by use of the-voltage (and current) at the output terminals 30 and 3| whenever line 5| is opened.

Referring first to Fig. 2, that portion of a safety device which includes a magnetic core 60 and an armature BI is shown schematically, said armature 6| being operatively connected in known devices to any suitable valve, switch member, or other member to be controlled (not shown). An electromagnet winding 62 is provided on said magnetic core 69 and is connected to a thermocouple63. Upon sufficient differential heating between the hot and cold junctions of said thermocouple, the magnetic core 60 is energized to maintain armature 6| against the pole faces 64 thereof, when armature 6| has been moved into engagement with said pole faces, manually or in any other suitable way. As long as electromagnet winding 62 is so energized, armature 6| is therefore maintained in the position illustrated against gravity, or a spring or other force, tending to separate the armature from the pole faces 64.

In conformity with one embodiment of the present invention as shown schematically in Fig. 2, asecond electromagnet winding 65 is provided on the core 6?! and connected to the terminals 30' and 3| which in turn are connected through any suitable lines with the output terminals 30 and 3| of Fig. l. As'long as the switch 50 of Fig.- 1 is closed and the alternating current output terminals 35 and SI supply a zero or a negligible amount of electrical energy to winding 65 through terminals 39 and 3|, depending on the exactness with which the voltages of the secondary windings l2 and 22 are made to match each other, retention of the armature 6| in its winding 1 I operative position as shown is solely under the control of the thermoelectric circuit 33, 62. Upon occurrence of an abnormal condition which would cause opening of the line 5|, as by opening the switch 50, the alternating current now available at the terminals 30 and 3| of Fig. 1 is applied through the terminals 30' and 3| to electromagnet winding 65 in Fig. 2. The magnetic field produced by electromagnet winding 65 will, with suitable alternating current flowing therein, cause the net magnetic flux of the electromagnet to fall periodically below that required to maintain armature 6| in the attracted position illustrated, thereby permitting armature 6| to move away from the pole faces 64 to actuate the associated safety device to inoperative position. Thus, opening switch 53 in response to an abnormal condition, or other opening of the line 5|, causes the safety device to move to its inoperative position even though normal thermo-electric current continues to flow in electr-omagnet winding 62.

Fig. 3 indicates schematically another application of the control device of Fig. 1 to a thermoelectrically controlled mechanism, like parts being indicated by like reference numerals. In this figure thermocouple 63 supplies energy to electromagnet winding 62 on core 60, but one lead 65' between the thermocouple 63 and the winding 62 includes in series the secondary winding 12 of a transformer 10. Primary winding ll of transformer Ill is connected to terminals 30' and 3| which in turn are connected in any suitable way to the output terminals 30 and 3| of mainder flows through the electromagnet winding 62, the net current flowing through the latter winding being the result of the superposition of the direct current produced by thermocouple 63 and the said remainder portion of the alternating current. With a suitable alternating current component flowing in the electromagnet winding 62, the magnetic flux will periodically pass through the minimum value required to maintain armature 6| in its attracted position, and armature 6| will thereupon move to its inoperative position.

To illustrate the actual operating characteristics of the device of Fig. 1 when used in the manner indicated schematically in Fig. 4 in controlling a commercial thermo-electric shutofi valve, similar transformers l0 and were used,

Fig. 1. Under normal operating conditions with the line 5| closed at 50, there is zero or negligible energy flow into primary winding II, and hence zero or a negligible alternating current is induced in the secondary winding 12. Under this condition the direct current generated at the thermocouple 63 energizes the electromagnet winding 62 to maintain armature 6| in contact with the pole faces 64, thereby maintaining the associated safety device in its operative position. Upon occurrence of an abnormal condition which opens the line 5|, as at 5|], energy is supplied to the output terminals and 3| of Fig. 1, and flows through any suitable connections to the terminals 30 and 3| and through the primary of transformer 10. This induces voltage in the secondary winding I2, causing an alternating current to be superimposed on the direct current generated by the thermocouple 63, and the resultant current now flows through electromagnet winding 62. With an alternating current component of suitable magnitude the magnetic. flux produced by winding 62 will periodically fall below the minimum value necessaryto maintain armature 6| in its attracted position, and armature 6| will therefore move to its inoperative position.

In the embodiment shown schematically in Fig.

4, the alternating current output from the ter- 7 minals3ll and 3| of Fig. 1 is applied through the terminals 30 and 3| respectively, to the thermocouple leads 65 and 66. As viewed from the terminals 30' and 3| thermocouple 63 and electromagnet winding 62 are connected in parallel. p

When line 5| is closed at 50 no alternating current or negligible alternating current is supplied to the terminals30', 3|. Upon opening of the line 5|, as at 50, however, alternating current from the terminals 30 and 3| is applied to the terminals 30' and 3| and thence to the thermocouple leads 65 and 66. Part of this current flows through the thermocouple 63 and the retheir secondary windings having a 60 cycle impedance of approximately 0.26 ohm. each. An input voltage of approximately volts, 60 cycles, was applied to the leads 40 and 4|, the voltage at each of the secondary windings I2 and 22, with switch 50 closed, being approximately 1.2 volts. With the output terminals an and 3| of Fig. 1 connected to the terminals 30' and 3|"of Fig. 4, opening of the switch 50 increased the current through the terminals 30' and 3| from zero to approximately 3.25 amperes. This alternating current superimposed on the direct current generated by the thermocouple 63, and which normall held the valve of the safety device in open position, was sufiicient to cause the valve to close.

It will therefore be perceived that the present invention provides an electric device of simple construction which may be readily connected into existing as well as applied to new circuits and which as long as the control circuit is closed, generates substantially no voltage at the output terminals thereof, but upon a break in or other opening of the line including one of the primary windings, an impulse is generated at the output terminals which can be used to actuate electrical or electromagnetically controlled devices. As applied to the actuation of thermoelectrically controlled devices, the alternating current at the output terminals 30 and 3| may be superimposed on the direct current generated by a heated thermocouple, or it may be applied to an electromagnet in circuit with the thermocouple, so that the net current value or'the net magnetic flux will periodically pass through a predetermined minimum value and thereby cause the thermoelectrically controlled device to act as if the thermoelectric current had failed or decreased below a predetermined value even though thermoelectric current is still being generated normally.

While the embodiments of the invention illustrated on the drawings have been described with considerable particularity, it is to be expressly understood that such embodiments are for purposes of illustration only, and are not to be construed as definitions of the limits of the invention, as the invention may receive a variety of expressions, as will now be apparent to those skilled in the art, while changes may be made in the details of construction, arrangement, electrical parameters, etc., and parts may be replaced by equivalent parts, without departing from the spirit of this invention. Reference is therefore to be had to the appended claims for a definition of said invention.

What is claimed is:

1. In an electrical energizing means for a control device of the character including a thermoelectric circuit having therein a thermocouple and an electromagnetic means provided with an armature operatively connected to a means to be controlled-and retained in operative position by said electromagnetic means while normal thermoelectric current is being generated by said thermocouple, the combination of means for actuating said electromagnetic means to effect release of said armature notwithstanding continued generation of thermoelectric current comprising a control circuit including output leads, input leads operatively connected to a source of alternating current and means in said control circuit having circuit connections to said input leads for imposing substantially zero voltage across said output leads when the circuit connections from said means to said input leads are completeand operable to impose a, substantial voltageacross said output leads upon interruption of a line in said connections, and means electrically connected to said output leads and associated with said electromagnetic means ,for applying alternating current in said output leads to said electromagnetic means to reduce the net effect of said thermoelectric current on said electromagnetic means sufiiciently to elfect release of said armature. I

.2. In an electrical energizing means for a control device of the character including a thermoelectric circuit having therein a thermocouple and an electromagnetic means provided with a coil and an armature operatively connected to a means to be controlled and retained in operative position by said electromagnetic means while normal thermoelectric current is being generated by said thermocouple, the combination of means for actuating said electromagnetic means to effect release of said armature notwithstanding continued generation of thermoelectric current comprising a control circuit including output leads, input leads operatively connected to a source of alternating current and means in said control circuit having circuit connections to said input leads for imposing substantially zero voltage across said output leads when the circuit connections from said means to said input leads are complete and operable to impose a substantial voltage across said output leads upon interruption of a line in said connections, and means electrically connected to said output leads and associated with said electromagnetic means for applying alternating current in said output leads to said electromagnetic means to reduce the net effect of said thermoelectric current on said electromagnetic means sufficiently to effect release of said armature, said last named means includ ing 'a second coil associated with said electromagnetic means and electrically connected to said output leads and operable to decrease the net magnetic fiux'acting on said armature when substantial voltage exists across said output leads.

3. In-an electrical energizing means for a control device of the character including a thermoelectric circuit having therein a thermocouple and an electromagnetic means provided with an armature operatively connected to a means to be controlled and retained in operative position by said electromagnetic means ,while normal thermoelectric current is being generated by said. thermocouple, the combination of means for actuating said electromagnetic means to efiect release of said armature notwithstanding continued generation of the thermoelectric current comprising a control circuit including output leads, input leads operatively connected to a source -of :alternating current and means in said control circuit having circuit connections to said input leads for imposing substantially zero voltage acrosscsaid'output leads when the circuit connections from said means to said input leads are complete andoperable to impose a substantial voltage across said output leads upon interruption of a line inzsaid connections, andmeans electrically connected tosaid output leads and associated withsaid electromagnetic means 'for applying alternating current in said output leads to said electromagnetic means to reduce the net efiect'of said thermoelectric current on said electromagnetic means sufliciently to efiect release of said armature,

said last namedmeans including a transformer having a secondary in'said thermoelectriccircuit and a primary electrically connected to said output leads. H

4. In an'electricalenergizing meansforxa control device of the character including a thermoelectric circuit having therein a thermocouple and an electromagnetic means provided with an armature operatively connected to a means to be controlled and retained in operative position by said electromagnetic means while normal thermoelectric current is being generated by said thermocouple, the combination of'means for-actuating said electromagnetic means to effect release of saidarmature notwithstandingcontim ued generation of thermoelectric current comprising a control circuit including output leads, input leads operatively connected to a source of alternating current and means in said control circuit having circuit connections to said input leads for imposing substantially zero voltage across said output leads when the circuit connections from said means to said input leads are complete and operable to impose a substantial voltage across said output leads upon interruption of a line in said connections, and means,

electrically connected tosaid output leadsand associated with said electromagnetic means for applying alternating current in said output leads to said electromagnetic means to reducethe net effect of said thermoelectric current on said electromagnetic means sufficiently to effect release of said armature, said last named means including leads electrically connecting said output'leads in parallel with said-thermocouple and electromagnetic means.

5. In an electrical energizing means for a control device of the character including a thermoelectric circuit having therein a thermocouple and an electromagnetic means provided with an armature operatively connected to a means to be controlled and retained in operative position by said electromagnetic means while normal thermoelectric current is being generated by said thermocouple, the combination of means for actuating said electromagnetic means (to ellectrelease of said armature notwithstanding continued generation of thermoelectric current comprising a control circuit including output leads, input leads operatively connected to a sourceof alternating current and a pair of transformers having secondaries in series with said output substantial voltage across said output leads upon opening of the circuit through one of said primaries while the circuit through the other primary remains closed, and means electrically connected to said output leads and associated with said electromagnetic means for applying alternating current in said output leads to said electromagnetic means to reduce the net effect of said thermoelectric current on said electromagnetic means sufiiciently to effect release of said armature.

6. In an electrical energizing means for a control device of the character including a thermoelectric circuit having therein a thermocouple and an electromagnetic means provided with a coil and an armature operatively connected to a means to be controlled and retained in operative positions by said electromagnetic means while normal thermoelectric current is being generated by said thermocouple, the combination of means for actuating said electromagnetic means to effect release of said armature notwithstanding continued generation of thermoelectric current comprising a control circuit including output leads, input leads operatively connected to a source of alternating current and a pair of transformers having secondaries in series with said output leads and primaries having parallel connections with said input leads, said transformers being so constructed and connected to said leads that the additive effect of the [current] voltage in said secondaries produces substantially zero voltage across said output leads when the circuits through both primaries are closed but operable to impose a substantial voltage across said output leads upon opening of the circuit through one of said primaries while the circuit through the other primary remains closed, and means electrically connected to said output leads and associated with said electromagnetic means for applying the alternating current in said output leads to said electromagnetic means to reduce the net efiect of said thermoelectric current on said electromagnetic means sufficiently to effect release of said armature, said last named means including a second coil associated with said electromagnetic means and electrically connected to said output leads and operable to decrease the net magnetic flux acting on said armature when substantial voltage exists across said output leads.

7. In an electrical energizing means for a control device of the character including a thermoelectric circuit having therein a thermocouple and an electromagnetic means provided with an armature operatively connected to a means to be controlled and retained in operative position by said electromagnetic means while normal thermoelectric current is being generated by said thermocouple, the combination of means for actuating said electromagnetic means to effect release of said armature notwithstanding continued generation of thermoelectric current comprising a control circuit including output leads, input leads operatively connected to a source of alternating current and a pair of transformers having secondaries in series with said output leads and primaries having parallel connections with said input leads, said transformers being so constructed and connected to said leads that the additive effect of the [current] voltage in said secondaries produces substantially zero voltage across said output leads when the circuits through both primaries are closed but operable to impose a substantial voltage across said output leads upon opening of the circuit through one of said primaries while the circuit through the other primary remains closed, and means electrically connected to said output leads and associated with said electromagnetic means for applying the alternating current in said output leads to said electromagnetic means to reduce the net effect of said thermoelectric current on said electromagnetic means sufficiently to effect release of said armature, said last named means including a transformer having a secondary in said thermoelectric circuit and a primary electrically connected to said output leads.

8. In an electrical energizing means for a control device of the character including a thermoelectric circuit having therein a thermocouple and an electromagnetic means provided with an armature operatively connected to a means to be controlled and retained in operative position by said electromagnetic means while normal thermoelectric current is being generated by said thermocouple, the combination of means for actuating said electromagnetic means to effect release of said armature notwithstanding continued generation of thermoelectric current comprising a control circuit including output leads, input leads operatively connected to a source of alternating current and a pair of transformers having secondaries in series with said output leads and primaries having parallel connections with said input leads, said transformers being so constructed and connected to said leads that the additive effect of the [current] voltage in said secondaries produces substantially zero voltage across said output leads when the circuits through both primaries are closed but operable to impose a substantial voltage across said output leads upon opening of the circuit through one of said primaries while the circuit through the other primary remains closed, and means associated with said electromagnetic means for applying the alternating current in said output leads to said electromagnetic means to reduce the net effect of said thermoelectric current on saidelectromagnetic means sufilciently to efiect release of said armature, said last named means including means electrically connecting said output leads in parallel with said thermocouple and electromagnetic means.

PAUL L. BETZ.

REFERENCES CITED The following references are of record in the file of this patent or the original patent:

UNITED STATES PATENTS Number Name Date 1,539,658 Fitzgerald May 26, 1925 2,241,127 Harder May 6, 1941 2,306,578 Wetzel Dec. 29, 1942 2,351,277 Mantz June 13, 1944 2,428,747 Ziebolz Oct. 7, 1947 

